This invention relates to Alarm Check Valves.
Alarm check valves are used in wet pipe automatic sprinkler systems and serve both as an alarm valve to indicate when a sprinkler head has operated, and is a check valve that prevents back flow from a sprinkler system.
Hitherto, alarm check valves have been of large size, accommodating a pivoted clapper within the body of the valve with the valve body being necessarily longer than the diameter of the clapper. Such alarm valves have been permanently installed in the main pipeline to the sprinkler system, and have required the provision of an inspection hatch on the side of the alarm body to enable the clapper to be inspected.
It is an object of this invention to provide an improved alarm check valve, which can be readily removed from the pipeline for servicing.
In one aspect, the invention provides an alarm check valve, said valve including an annular body providing a main flow passage therethrough, opposite ends of said body having substantially flat faces capable of being held between oppositely disposed flanges of a pipeline, a pivotally mounted clapper within said body capable of closing off said main flow passageway, and capable of being pivoted into an open position in which said clapper extends beyond one of said end faces of said body, and a secondary flow passageway in said body leading from a portion of said body covered by said clapper when in the closed position, leading to an outlet port for communication with a sensor capable of detecting flow through said passageway.
By this means, the alarm check valve of this invention is capable of being inserted in a pipeline, is of relatively compact form, and can be removed from the pipeline for inspection as it can be clamped in place by bolts or the like between the oppositely disposed flanges of the pipeline which can be readily removed to enable the alarm check valve to be removed from the pipeline.